In the inline chat, I had enabled Sonnet 4.5, but the one actually used was Sonnet 3.5. And I was charged in Sonnet 4.5 fee. What’s the deal with that !?
Cursor never swaps your chosen models. When you pick a specific model, your request is always handled by that model without switching.
Important note: all Anthropic models are named “Claude,” and Claude 4 was trained on data that included info about Claude 3.5 Sonnet. Also, models accessed via API without a system prompt don’t have self-knowledge.
Users have also checked this with the direct Anthropic API - models do identify themselves unreliably, which confirms this is a model behavior, not a Cursor issue.
If you’re seeing concrete quality issues with the model (beyond self-identification), please share:
The Request ID of the problematic request (chat context menu - Copy Request ID)
Specific examples of incorrect behavior
Steps to reproduce
This will help the team verify if there’s a real model issue.
